Exhaust system



. J. H. LEWIS EXHAUST SYSTEM Nov. 25, 1958 INVENTOR. B M22222 1% Jam; $83M 2 Sheets-Sheet 1 ATTORNEY Filed Ilay 24. 1956 Nov. 25, 1958 J. H. LEWIS 2,861,418

EXHAUST SYSTEM Filed May 24. 1956 2 Sheets-Sheet 2 IN VEN TOR.

ATTORNEY United States Patent EXHAUST SYSTEM James H. Lewis, East Lansing, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application May 24, 1956, Serial No. 587,032

Claims. (Cl. 60-29) This invention relates to exhaust systems for internal combustion engines and has particular relation to exhaust systems having single or plural outlets for discharging exhaust gas to the atmosphere.

-It has been the practice to construct exhaust systems for internal combustion engines for automotive applications, generally, either as single or dual exhaust systems. In constructing single exhaust systems for V-type engines employed for automotive and other purposes, it has been the practice to provide an exhaust manifold for each bank of cylinders, an exhaust cross-over passage for heating the induction system of the engine, and to connect the two manifolds to a single exhaust conduit leading to the rear of the vehicle. An exhaust heat valve may be provided in the outlet from one of the manifolds to compel the flow of exhaust gas from one bank of cylinders to the other, through the cross-over passage. This is desirable to heat the induction system of the engine. The sound attenuating device or a mufller employed may be tuned to operate with all of the cylinders of the engine because the exhaust gas from all of the cylinders of the engine flows to the atmosphere through the same conduit.

If a dual exhaust system is employed it has been the practice to connect exhaust conduits to the outlet from each exhaust manifold and to provide a suitable sound attenuating device or mufiler in each exhaust conduit. If such a system is employed in a V-type eight cylinder engine it will be apparent that each mufller normally must be tuned to operate on the impulses resulting from the operation of one bank of four cylinders. Each muffler might therefore be described as a four cylinder tuned mufiler. With the single exhaust system previously described the mufller might be said to be an eight cylinder tuned muffler.

It has been discovered that building four cylinder mufflers is considerably more diflicult and expensive than building eight cylinder mufflers, if the same degree of sound attenuation is to be obtained. It has also been found to be undesirable to construct different exhaust systems for the same engine, in instances where the same engine may be provided with a single or dual exhaust system for different installations.

It is now proposed to construct a single exhaust system that is easily converted into a dual exhaust system and that will operate in either event with rnufilers tuned to all of the cylinders of the engine.

In the drawing:

Figure 1 is a front elevational view of an internal combustion engine embodying an exhaust system embracing the principles of the invention;

Figure 2 is a fragmentary side elevational view of the exhaust system, the lower part of the engine being indicated in dot and dash lines;

Figure 3 is a plan view of an automobile frame with a part of the exhaust system positioned therein;

Figure 4 is a side elevational view of a heat control valve employed in the outlet leading from one of the exr 2,861,418 Patented Nov. 25, 1958 .An induction system 13 supplies fuel and air charges,

which are successively burned in the several cylinders of the engine, to provide engine events that occur in regularly timed relation. The exhaust gas resulting from the burning of the charges in the cylinders in the cylinder bank 11 is discharged to an-exhaust manifold 14. The exhaust gas resulting from the burning of the charges in the cylinders in the cylinder bank 12 is discharged to an exhaust manifold 16. The successive charges supplied to the cylinders are adapted to flow through inlet manifold passages indicated at 17 and 18. To heat the charges supplied by the passages 17 and 18 it has been the practice to employ an exhaust cross-over passage 19, which is constructed to extend between the cylinder banks 11 and 12, through the heads of the engine and to the exhaust manifolds 14 and 16. To cause exhaust gas to flow from one bank of cylinders to .the other, through the exhaust cross-over passage 19, it has been customary to employ a heat control valve 21 in the outlet leading from one of the manifolds. The heat control valve may be an unbalanced valve such as that indicated at 22 and may be mounted for rotation on a shaft 23 extending across the manifold outlet 24 in the body 26 which may be secured to the manifold in any suitable manner. A weight 27 on the end of an arm 28 secured to the end of the shaft 23 outside the body 26, may be positioned to oppose the opening of the valve 22. The opening of the valve 22 also may be opposed by thermostat 29 secured between the end of the shaft 23 and a pin 31 projecting from the body 26. As the engine temperature increases the resistance of the thermostat 29 to the opening of the valve 22 decreases. When the valve 22 is in the position shown in Figure 5 the exhaust gas in the manifold 14 will flow to the manifold 16 through the cross-over passage 19. This will heat the charges of fuel and air flowing to the cylinders through the passages 17 and 18 and will improve the operation of the engine when the engine is started cold. As the engine speed or temperature increases the valve 22 will open to permit the exhaust gas from manifold 14 to flow through the outlet 24.

To construct a single outlet exhaust system it is only necessary to provide a cross-over conduit 32 to be secured to the outlet from the manifold 14 leading through the heat control valve 21, and to an outlet extension 33 leading from the manifold 16. A single exhaust conduit 34 then may be connected to the outlet extension 33 in a manner to receive the exhaust gas from manifold 16 supplied through the outlet 33 and from manifold 14 supplied through the heat control valve 21 and the conduit 32. To attenuate the sound resulting from the operation of the engine it is necessary only to employ in the conduit 34, a suitable sound attenuating means or mufiler such as that indicated at 36. The muffler 36 may be made in any desired number of sections or in a single section as illustrated. Since all of the exhaust gas from the groups of cylinders in the banks 11 and 12 flows through the single conduit 34, the muffler 36 may be tuned to the impulses involved in the operation of all of the cylinders of the engine. If the engine 10 is an eight cylinder engine, the mufiler 36 may be an eight cylinder tuned muffler of suitable capacity.

In the event it is desirable to provide a dual outlet exhaust system it is only necessary to change a single part of the exhaust system previously described and to provide in each exhaust conduit an eight cylinder tuned muffler of suitable capacity. For a. dual outlet system the conduit 32 may be provided with a side branch coupling such as that indicated vat 37. A second exhaust conduit 38 embodying an eight cylinder muffier 39 then may be connected to the side" branch coupling 37. In the dual system it will be noted that the tWo mufliers 36 and 39 maybe tuned to the oper'ation of all eight cylinders of the engine 10, notwithstanding that the mufilers are in separate outlet conduits. When the heat control valve 22 is closed both banks of the cylinders of the engine will communicate with both mufilers through the exhaust manifolds 14 and 1 6 and the cross-over passage 39. Whenthe valve2 2 is opened both manifolds will communicate directly .with'each group of cylinders through thecross-over conduit 3 2and the exhaust manifolds l4 a r'1 d16. I

If "the cross-over con'duit 32 were not employed in the dual system the mufllers 36 and 39 normally would be tuned to impulses resulting from the operation of the cylinders in one bank of cylinders of the engine. The muffier's' for the engine 10, therefore, might be said to be'fou'r cylinder 'tun'ed muffiers. If the valve 22 were closed, then all of the cylinders of the engine would be operating on themuffier 36 until the engine temperature or speed had been increased sufficiently to open the 'valve 22. Under such circumstances the engine would be very noisy. 'It 'Would be operating on a muffier not tuned to the operation of all eight of the cylinders of the engine.

I claim:

1. An exhaust system for internal combustion engines having different groups of cylinders synchronized and timed to fire and to exhaust in'consecutive order and in regularly spaced relation and provided with exhaust manifold means for each group of cylinders and with a first exhaust cross-over passage extending between said manifold means and with a heat control valve controlling the flow of exhaust gas from one of said manifold means through a manifold outlet leading from said one of said manifold means, and comprising a pair of exhaust conduits leading from said engine and having muffler means a in each of said conduits, each of said mufiler means being tuned to the resonant frequency resulting from the operation of all of said cylinders in said groups, and a second exhaust cross-over passage extending between said manifold means, said second cross-over passage being connected to said manifold means through manifold outlets leading from said manifold means, one of said manifold outlets being said manifold outlet controlled by said heat control valve, said exhaust conduits both being connected at all times to said first and second cross-over passages and said manifold means for said groups of cylinders, the connection of said exhaust conduits with said one of said manifold means being through said first exhaust cross-over passage when said heat control valve closes said one of said manifold outlets.

2. An exhaust system for internal combustion engines as defined by claim 1 and in which one of said exhaust conduits is connected to said second cross-over passage between said heat control valve and the other of said manifold outlets.

3. An exhaust system for internal combustion engines as defined by claim 1 and in which said heat control valve is engine speed and temperature responsive, said valve being adapted to open as said engine speed and temperature increases.

4. An exhaust system for internal combustion engines as defined by claim 1 and in which said exhaust crossover passage is adapted to heat the induction system of said engine when said heat control valve tends to restrict the flow of exhaust gas from said one of said manifold outlets.

5. An exhaust system for internal combustion engines as defined by claim 1 and in which the mufiler means employed in the system is tuned to the operation of all of the cylinders of the engine.

References Cited in the file of this patent UNITED STATES PATENTS 1,761,960 Armitage June 3, 1930 2,305,946 Wilson et al. Dec. 22, 1 942 2,603,199 Mosely July 15,1952 2,720,935 Lysholm et a1 Oct. 18, 1955 

